MERCURY, CADMIUM AND LEAD ACCUMULATION IN ANTARCTIC MOSSES GROWING ALONG NUTRIENT AND MOISTURE GRADIENTS

Accumulation of Mg, Cd and Pb by moss was studied in a coastal ice-fre e area (Edmonson Point, northern Victoria Land) in relation to the wat er and nutrient availability and substratum characteristics. Although metal concentrations in surface soils were among the lowest ever repor ted from remote areas, those of Hg and Cd in mosses were higher being in the same range as those usually reported in regional surveys in the northern hemisphere. By contrast, Antarctic mosses showed very low Pb concentrations, and no impact from local human activities was detecte d. Marine aerosols, seabird guano and volcanic emissions appeared to b e the more probable sources of Cd and Hg. Besides atmospheric depositi on, the main pathway of metals to mosses was probably through evapo-tr anspiration at their surface which determines an upward migration of i ons and their bioaccumulation.